PHOTOREARRANGEMENTS OF 2,4-DISUBSTITUTED PHENYL ESTERS

Various 2- and 2,4-disubstituted phenyl esters have been irradiated by ultraviolet light, and the products have been isolated and characterized. The relative large numbers of products obtained (up to six) showed that at least five different reactions were taking place: (1) photo Fries rearrangements resulting in o-hydroxyacetophenones, (2) photo Fries rearrangements in which methoxy groups were displaced resulting in o- and p-hydroxyacetophenones, (3) cleavage reactions resulting in phenols and in one case benzaldehyde, (4) decarboxylation reactions resulting in methylbenzene and biphenyl compounds, and (5) phototransposition of the ring carbon atoms resulting in rearranged methylbenzene and biphenyl compounds. Mechanisms for the various reactions are discussed. © 1968, American Chemical Society. All rights reserved.